Counterfeit consumer goods, commonly called knock-offs, are counterfeit or imitation products offered for sale. The spread of counterfeit goods has become global in recent years and the range of goods subject to counterfeiting has increased significantly.
Expensive watches (and spare parts for watches) are vulnerable to counterfeiting, and have been counterfeited for decades. A counterfeit watch is an unauthorized copy of a part or all of an authentic watch. According to estimates by the Swiss Customs Service, there are some 30 to 40 million counterfeit watches put into circulation each year. It is a common cliché that visitors to New York City are approached on the street by vendors with a dozen such counterfeit watches inside their coats, offered at bargain prices. Extremely authentic looking, but very poor quality counterfeit watches with self-winding mechanisms and fully working movements can sell for as little as twenty dollars. The problem is becoming more and more serious, with the quality of the counterfeits constantly increasing. For example, some counterfeits' materials are of remarkably passable quality and may look good to the untrained eye and work well for some years, a possible consequence of increasing competition within the counterfeiting community. Counterfeit watches cause an estimated $1 Billion loss per year to the watch industry.
Authentication solutions that have been used for protection of consumer goods from counterfeiting are often based on marking the item with a specific material, code, or marking, engraving, etc. However, these methods modify the nature and the appearance of the object, and this is often not acceptable in the watch (and other luxury items) industry, where the design of the object and its visual appearance is of paramount importance.
Counterfeiters often focus on the outer appearance of the watch and fit cheaper components inside, because the potential buyer tends to focus more on the outward appearance of the piece. It is, therefore, desirable, when assessing the authenticity of a timepiece, to have as much information as possible. It is furthermore desirable not to have to open the timepiece when checking the authenticity, as the operation requires specialized equipment and procedures, which may impact on the performance and/or integrity of the piece (e.g., water tightness), and which may invalidate the manufacturer's warranty.
It is, therefore, desirable to be able to authenticate a timepiece in a manner that is as non-invasive and as reliable as possible without having to open the timepiece.